(Step 8). The DNS server returns the response to the proxy server (Step 9). Finally, the proxy server uses the obtained IP address of www.someother.com. to contact it and provides the necessary information to the client (Step 10).

A computer in the ZZZ Corporation needs to resolve a DNS query for www.someother.com. It submits an appropriate query to the assigned DNS server (Step 1). If its cache contains necessary data, then the server will respond to the client. Otherwise the server forwards the query to the DNS server containing the zzz.com. zone (Step 2). This server forwards the query to the external server (Step

3)through the firewall. The latter performs the name resolution similar to the previous case (Steps 4-9) and passes the result to the client though the firewall and the chain of participated in the resolution servers (Steps 10-12). Then the client uses the resolved IP address of www.someother.com. to contact it through the firewall and download the desired web page.

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Microsoft windows 2000 DNS manual Windows 2000 White Paper